NU 2020-087
INVENTORS Yip-Wah Chung* Q. Jane Wang* Erica M. Hartmann* Arman M. Khan Seyon Vaynman Dieter Isheim
SHORT DESCRIPTION Novel copper-precipitation-strengthened steel for inexpensive bactericidal and virucidal surfaces
ABSTRACT Northwestern researchers have developed novel low-carbon ferritic steels strengthened by nanometer-sized copper precipitates. These steels use a small fraction of copper (1-4%), which substantially improves the strength and corrosion resistance of the resultant steel. Atom probe tomography shows the copper exists as nanoscale precipitates in close proximity within the steel matrix. At just 2.5% copper, these materials have demonstrated bacterial resistance against E. coli HCB84 which is similar to several copper alloys which have already received EPA approval as antimicrobial surfaces. Those alloys, however, have a much higher fraction of copper (minimally 60 %) raising the cost and deteriorating the mechanical properties. Further, pure copper has demonstrated virucidal capacity against SARS CoV-2. Based on these initial observations, it is expected that the copper-precipitation-strengthened steel developed by Northwestern researchers will maintain much of the bactericidal and virucidal properties of pure copper owing to the tight packing of nanoscale copper domains. Compared to pure copper, however, these materials have additional beneficial characteristics, including higher strength, higher chemical resistance, and lower cost while maintaining the appearance of common stainless-steel touch surfaces. These factors will enable the deployment of this material for high-touch surfaces within the medical, industrial, and home setting. Additionally, the steel developed by Northwestern researches has already been deployed in two Illinois bridges with over 400 metric tons produced. This demonstrates the scale at which this material can be manufactured.
APPLICATIONS
ADVANTAGES
IP STATUS A provisional patent application has been filed.
3D map of nanoscale copper precipitates (red) within a steel sample roughly 80nm x 80nm x 160nm. Blue dashed line represents 100nm diameter-showing an approximate representation of a pathogens interaction with many copper precipitates.